Acetylenic glycol deicer



rates at 3,020,136 Patented Feb. 6, 1062 This invention relates to gasoline compositions adapted to improve the operation of internal combustion engines. It is more particularly concerned with motor fuels that provide improved engine operation under cool, humid weather conditions.

As is well known to those skilled in the art, frequent stalling of automobile engines, especially during the warmup period, has been a common occurrence. This difliculty is most pronounced in postwar cars having automatic transmissions and a consequent limit on the maximum permissible idle speed, although it also occurs in cars without automatic transmissions. Stalling of this type, of course, is a definite safety hazard, as well as a decided inconvenience in frequent restarting of the engine.

It is now recognized that stalling during the warmup period is attributable to the formation of ice on the throttle plate and the carburetor barrel near it. The water which forms the ice does not come from the gasoline, i.e., as entrained water, but from the air that enters the carburetor. As has been mentioned hereinbefore, stalling generally occurs in cool, humid weather, when the temperatures are above about 30 F. and below about 60 F. and the relative humidity is about 65 percent and higher, up to 100 percent. The most critical conditions are temperatures of 35-40 F. and 100 percent relative humidity.

As the gasoline evaporates in the carburetor, it reduces the temperature of the surrounding metal by as much as 40 F. Moisture in the incoming air comes in contact With these parts and begins to build up ice on the throttle plate and in the carburetor barrel. The more moist this air is, the greater the buildup of ice. Then, when the engine is idled, the throttle plate closes and the ice chokes off the normal small flow of air through the small clearance between the throttle plate and the carburetor wall. This causes the engine to stall. The engine can usually be restarted when the heat from the exhaust manifold melts the ice sufiiciently. However, stalling will continue until the engine is completely warmed up.

Gasoline is a mixture of hydrocarbons having an initial boiling point falling between about 75 F. and about 135 F. and an end-boiling point falling between about 250 F. and about 450 F. The boiling range of the gasoline, of course, reflects on its volatility. Thus, a higher boiling gasoline will be less volatile and give less stalling difficulty. In modern engine operation, however, control of stalling by means of decreased volatility is not feasible, because other performance characteristics are affected.

It has now been found that stalling during engine warmup can be overcome simply and economically. It has been discovered that small amounts of certain acetylenic glycols, when added to motor gasoline, will overcome stalling difficulties attributable to carburetor icing.

Accordingly, it is an object of this invention to provide an improved motor fuel. Another object is to provide a motor fuel adapted to prevent stalling during engine warmup in cool, humid Weather. A specific object is to provide an antistall gasoline containing certain acetylenic glycols. A very specific object is to provide a motor gasoline containing 3,6-dimethyl-4-octyne-3,6-

2 diol. Other objects and advantages of this invention will become apparent to those skilled in the art, from the following detailed description.

In general, this invention provides a motor gasoline containing a small amount, sufficient to inhibit stalling, of acetylenic glycols having the formula,

wherein R is an alkyl group containing between 2 and 4 carbon atoms.

The acetylenic glycols utilizable herein are those having the structure:

(EH3 CH3 l to in which R is an alkyl radical of 2 to 4 carbon atoms. Examples of the glycols are 4,7-dimethyl-5-decyne-4,7- diol; 2,4,7,9-tetramethyl-5-decyne-4,7-diol; and 3,6-dimethyl-4-octyne-3,6-diol. As is demonstrated hereinafter, the latter compound is an outstanding, and preferred, antistall additive. These compounds are readily available commercially. They can be prepared, for example, by the addition of acetylene and ketones.

The amount of acetylenic glycol that is added to the motor gasoline will vary between about 0.005 percent and about 0.1 percent, by weight, of the gasoline. In preferred practice, amounts varying between about 0.01 percent and about 0.05 percent, by weight, are used.

The antistall additives of the invention may be used in the gasoline along with other antistall addition agents or other additives designed to impart other improved properties thereto. Thus, anti-knock agents, pre-ignition inhibitors, anti-rust agents, metal-deactivators, dyes, antioxidants, detergents, etc., may be present in the gasoline. Also, the gasoline may contain a small amount, from about 0.01 percent to about 1 percent, by weight, of a solvent oil or upperlube. Suitable oils, for example, include Coastal and Mid-Continent distillate oils having viscosities within the range of from about 50 to about 500 S.U.S. at F. Synthetic oils, such as diester oils, polyalkylene glycols, silicones, phosphate esters, polypropylenes, polybutylenes and the like, may also be used.

The following examples are for the purpose of illustrating the additives of this invention and demonstrating the efiectiveness thereof. This invention is not to be limited to the specific compositions set forth in the examples or to the operations and manipulations involved. Other materials and formulations as described hereinbefore can be used, as those skilled in the art will readily understand.

The ability of an additive to inhibit stalling is demonstrated in the following tests:

A standard Chevrolet engine, equipped with a Holley single downdraft carburetor, was mounted in a cold" room refrigerated to 45 F. A thermocouple was attached to the throttle plate shaft to record the plate temperature. A /z-inch insulating gasket was placed between the carburetor and manifold to prevent heat conduction. An asbestos sheet covered the entire manifold system to shield the carburetor from convection and radiation. A spray chamber and an ice tower was used to saturate the incoming air with moisture and to cool the air to about 35 F. before it entered the carburetor.

In conducting a test, the engine was first run for about 10 minutes at 2000 rpm. to bring the engine temperature to equilibrium. The engine was then shut off. When W the throttle shaft temperature rose to 40 F., the engine was restarted with the idle speed set at 450 rpm. so that the base fuel stalled at idle in seconds or less after a run-time of 20 to 40 seconds. Run-time means the time that the engine was run at 2000 r.p.m. before returning to idle.

All the runs were started when the throttle shaft reached 40 F. At the instant of starting, the throttle arm was moved to the 2000 rpm. position and a stop watch started. At the end of the selected run-time, the throttle was moved to the idle position. The time required to stall was recorded. Several tests were made at each run-time and averaged.

In evaluating an additive, the base fuel was first tested followed by several concentrations of the additive. The system was flushed between tests with the fuel to be run next. Any improvement caused by the additive was reflected in a longer run-time (as compared to the base fuel) to cause stalling in 10 seconds or less when the engine was idled. The more efiective the additive, the longer the run-time.

The gasoline used to test the additives contemplated herein was a blend of, by volume, 70 percent catalytically cracked gasoline and 30 percent natural gasoline. It had an ASTM boiling range of 98 F. to 387 F., with a midboiling point of 194 F.

Using this test gasoline, a series of blends were prepared. Each blend contained a difierent acetylenic glycol. The glycol used in each case, its concentration, and test It will be apparent from the data in Table I, that the acetylenic glycols are efiective antistall additives for gasoline, although they are not all equivalent in performance. Most show an increase in run-time of 50-100 percent. The material in Runs 2 and 3 (3,6-dirnethyl-4-octyne-3,6-

diol), however, is unexpectedly outstandingly superior. This compound increases run-time by 400 percent.

Although the present invention has been described with preferred embodiments, it is to be understood that modifications and variations may be resorted to, without departing from the spirit and scope of this invention, as those skilled in the art will readily understand. Such variations and modifications are considered to be within the purview and scope of the appended claims.

What is claimed is:

l. A motor gasoline containing a small amount, sulficient to inhibit stalling, of acetylenic glycols having the formula wherein R is an alkyl group containing between 2 and 4 carbon atoms.

2. A motor gasoline containing between about 0.005 percent and about 0.1 percent, by weight, of acetylenic glycols having the formula CH3 R-(J-CEO-d-R A H H wherein R is an alkyl group containing between 2 and 4 carbon atoms.

3. A motor gasoline containing between about 0.01 percent and about 0.05 percent, by weight, of 3,6-dimethyl-4-octyne-3,6-diol.

4. A motor gasoline containing between about 0.01 percent and about 0.05 percent, by weight, of 4,7-dimethyl-5-decyne-4,7-diol.

5. A motor gasoline containing between about 0.01 percent and about 0.05 percent, by weight, of 2,4,7,9- tetrarnethyl-S-decyne-4,7-diol.

References Cited in the file of this patent UNITED STATES PATENTS 2,701,754 Haworth et al Feb. 8, 1955 2,722,099 Wasserbach Nov. 1, 1955 FOREIGN PATENTS 760,105 Great Britain Oct. 31, 1956 1,136,678 France Dec. 29, 1956 

1. A MOTOR GASOLINE CONTAINING A SMALL AMOUNT, SUFFICIENT TO INHINIT STALLING, OF ACETYLENIC GLYCOLS HAVING THE FORMULA 